1. Field of Invention
The invention relates to a sheet guiding system and an image forming device having a sheet guiding system.
2. Description of Related Art
U.S. Pat. No. 6,435,499 discloses a conventional sheet guiding system of a center registration type in which different sized sheets are guided while their center positions are used as a reference. FIGS. 10A and 10B show a center registration type sheet guiding system similar to the one disclosed in U.S. Pat. No. 6,435,499. FIGS. 10A and 10B are a plan view and a sectional side view, respectively, of a conventional center registration type sheet feed cassette 100. FIG. 10A shows a positional relation between sheet guides and different sized sheets in the sheet feed cassette 100. Sheets 3 are sandwiched and guided by sheet guides that are movable in a sheet width direction. Large sized sheets are regulated by moving first and second movable guides 101, 102 inward, while small sized sheets are regulated by moving the first and second movable guides 101, 102 outward. In FIG. 10A, the first and second movable guides 101, 102 are placed farthest away from each other when guiding letter (LTR) and legal (LGL) size sheets, and placed close to each other with respect to the center line X, as shown by dash-double-dot lines, when guiding postcard sized sheets. The center positions of different sized sheets are the same in the sheet feed cassette 100. A rear guide 103 is also provided at the rear of a recess 100a to align the rear edges of the sheets. The rear guide 103 is movable in a sheet feed direction that is parallel to the center line X of different sized sheets. Sheets 3 are fed one by one by a sheet feed roller, and a portion 104 to receive a pressing force from the sheet feed roller is provided at the bottom of the sheet feed cassette 100.